DESCRIPTION (adapted from the Abstract): Preliminary results from this research team suggest that contrary to expectations, neurocognitive deficits among African American men infected with HIV-1 are related to alcohol consumption, but not to the use of cocaine. In this application, the Principal Investigator proposes to follow-up on those initial findings with a series of focused secondary analyses on the very rich dataset collected in the NIDA-funded African American Health Project (AAHP). The study is designed to examine the neurobehavioral effects of HIV/AIDS and substance use in a community sample of HIV-positive and HIV-negative African American men, arguably the largest community sample of high-risk African American who have been assessed with a comprehensive neurobiological, psychiatric, and psychosocial measures. Two parallel studies are proposed in this application. In Study #1, the researchers will examine the contribution of alcohol to high risk sexual behaviors, both independently and as modified by illicit drug use and other psychosocial co-factors in a sample of 190 HIV-positive and 312 HIV-negative men. In Study #2, they will examine the contribution of alcohol to neurocognitive functioning and neurcognitive caseness in the full sample of 502 men. The researchers will examine, also, the role of alcohol in neurophysiologic status and functioning as indexed by regional blood flow (rCBF) in a stratified sample of 118 HIV-positive and HIV-negative men using state-of-the-art neuroimaging techniques (MRI, MRS, SPECT). In these analyses, the researchers will take advantage of a unique dataset using, thereby, a relatively cost- effective means to enhance our understanding of the role alcohol plays in HIV disease in this understudied population.